Allotter-controlling system



A. E. LUNDELL ALLOTTER CONTROLLING SYSTEM Flled Sept 21 1923 Dec. 29 1925- bridge.

Patented Dec. 29, 1925.

UNITED STATES PATENT OFFICE.

ALBEN' E. LUNDELL, OF NEW YORK, N. Y., ASSIGNOR TO WESTERN ELECTRIC COM- PANY, INCORPORATED, OF NEW YORK. N. Y., A CORYORATION OF NEW YORK.

ALLOTTER-CONTROLLING SYSTEM.

Application filed September 21, 1923.

To all whom it may concern:

Be it known that I, ALBEN E. LUNDELL. a citizen of the United States of America, residing at New York, in the county of Bronx and State of New York, have invented certain new and useful Improvements in Allotter-Controlling Systems, of which the following is a full, clear, concise, and exact description.

This'application is a continuation in part of the application of Lundell and Clark, Serial No. 301,891, filed June 5., 1919.

This invention relates to a telephone exchange system and more particularly to an allotting system for use in determining the order in which apparatus shall be put into use.

It is an object of this invention to provide an improved, allotting system.

This invention is especially directed toward the provision of an improved central equipment by means of which a manual operator automatically selects a common equipment to assist her in transmitting calls from an incoming line through automatic switches, to a wanted subscriber.

It is the purpose of this invention to control an allotter by means of a Wheatstone The Wheatstone bridge when unbalanced associates common equipment with an operators position to be used for controlling the automatic switches.

A feature of this invention is in the pro- .vision of a plurality of common connecting units and a common allotter to control the association of said connecting units to any one of a plurality of operators positions.

A further feature of this invention is the ability of the Wheatstone bridge allotter to successively allot the connecting units to a plurality of operators initiating simultaneous calls.

These and other features of the invention will be apparent from the following descrip tion and accompanying drawing.

While the invention has been disclosed as particularly adapted for telephone systems, it will be apparent, however. from the following description that the invention has a Wider utility and by slight modification could be adapted for other control systems.

The accompanying drawing, illustrates a Wheatstone bridge allotter, upper right, a

connecting unit and associated sender, and

apparatus of an operatore position, lower Serial No. 663,977.

left. The operators position, sender and connecting unit are shown in diagrammatic form only. These parts of the drawing are described in detail in patent application of A. E. Lundell and E. H. Clark, Serial No. 654,106, filed July 27, 1923.

The allotter is connected to a plurality of operators positions and a plurality of connecting units. Each connecting unit has a switch, the same as switch 200. The contacts of all switches, such as switch 200, are multipled in such manner that certain contacts in each switch are connected to a particular operators position. In this manner the switch associated with each connecting unit has access to all of the operators positions.

Description of apparatus.

The allotter relay 301 is of the polarized type actuated from current flowing through its winding in one direction only. The allotter switch and switch 200 are of the well known step-by-step type controlled by a selfinterrupting magnet.

Detailed description.

Let it be assumed that the operator wishes to initiate a call in a system requiring that a common sender be associated with the operators position. To initiate such a call the non-locking start key 101 is actuated. A circuit is thus established to actuate relay 102 which may be traced from grounded battery through the contacts of key 104, winding of relay 102 to ground through the contacts of key 101. Relay 102 in operating establishes a locking circuit for itself through its left contact and armature, resistance 103 to ground. Relay 102 in attracting its right armature establishes a circuit to unbalance the Wheatstone bridge circuit of the allotter. This circuit may be traced from ground through the right armature and contact of relay 102, conductor 238, resistance 331 and over a divided path, one side of which may be traced through resistance 398 to grounded battery and the other side through the winding of polarized relay 301, resistance 330 to grounded battery. Relay 301 is operated in the circuit traced since the directior. of current flow is correct for its operation.

Relay 301 in attracting its armature establishes a cirt uit to operate relay 210. The

circuitmay be traced from grounded battery through the left winding of relay 210, switch arm 396 and its associated contact to ground through the armature and. contactof relay 301.; Relay. 210 in operatintg establishes a locking circuit for itself and an operating circuit for relay'208. The looking circuit may be traced from grounded battery through the right winding, right inner contact and armature of relay 210 to groundthrough the right inner normal contact" and armature otrelay 211'. The operating circuit for relay 208 may be traced from grounded battery through its winding, right inner contact and armature of relay 210 to ground through the right inner normal contact and armature of relay 211. Relay 210 in operating establishes a circuit to actuate switchmagnet 337. This circuit may be traced from grounded battery through tlie winding-and contacts of magnet 337, switch arm 397 and its associated contact to ground through the right outer armature and contact of relay 210. The allotter switch now rotates under the control of magnet 337 to locate an idle connecting unit where it will remain until the allotter /Vheatstone bridge: is again unbalanced. The ground traced from the right outer contact and armature of relay 210 to the contact associated with switch arm 39'? characterizes. this allotter switch position as busy to prevent the allotter switch from seizing this connecting unit until it hasagain become idle.

Relay 208 in attracting its right armature establishes a circuit to balance the /Vheat stone bridge. This circuit may be traced from groundthrough the right contact and armature of relay 208, conductor 399, resistance 332', resistance 330 to grounded battery. The ohmic resistance values of resistances'331 and'332 are thesame and the ohmic resistance values of resistance 3'98 and 330 are the same; Theretorethe current flow 'through'both legs of the VVheatstone bridge neutralizes the potential in the windings otnolar1zedrelay 301 to cause itsrelease. The o eration of relay 208 furtherv estab- 'lishes a circu t to rotate switch, 200; as hereinafter describedi to find the operators nosition in whichthecall is initiated. There are a plurality ot'operators positions the same astlie" one showninthe. accompanying drawing: Conductors the. same as 105 in e ch onerators position are connected from rue 'lett armatureoff' relays the same as 102 to separate contacts. associated. with brush 203'. Assuming'that'the relays "102 are normal inallpositions except the one in which the call is initiated; ground is connected through the" armature of the" relays 102' to all of the contacts associated with switch arm-203-'encept"the"contact associated with 5 relay"102 mithe-operators position initating a call. The operation of relay 208 thus establishes a circuit from grounded battery through the winding and contacts of switch magnet 209, left outer contact and armature of relay 208, left normal contact and arn1ature of relay 207, brush 203 and its associated COIltklCtSz'tO ground through the armature and contact of the normal relays 102 in other operators positions. Switch 200 now rotates until brush 203 is associated with the contact connected to the operated relay 102 in' the position. initiating the call. Ground potential is new supplied to magnet 209 through resistance 103. which is of such value as to prevent the operation of the stepping magnet and to remove the shunt path from the winding of relay 207 to allow the esta'blislunent of a circuit through its winding. This circuit may be traced from grounded battery through the winding and contacts of switch magnet 209, left. outer contact and arniiature of relay 208, winding of relay 207 to ground through the left inner contact and armature of relay 208. The current flow in the circuit traced is suiiicient to operate relay 207 but on account of the high resistance of relay 207 the current flow is insufficient to actuate switch magnet 209.

The operation. of relay 207 establishes a circuit to operate relay 211. This circuit may be traced from ground through the winding of relay 211. contact and arn'ia-ture of relay 207, brush 203 and its associated contact, let't armature and contact and the winding of relay 102. contacts ot key 104 to grounded battery. The operation 0t relay 211 establishes a circuit from ground through its right inner armature and contact',,resistauces 332 and 330 to grounded battery which maintains the balancing ground potential originally supplied at the right armatureot relay 208. The 0peration ot relay 211 furthcrestablishes a locking circuit for itself which may be traced from ground through its winding'and lett contact and armature. brush 203, left armature and contact and the winding of relay 102 to Q'roun'ded battery through the con tacts'ot key 10%. The operation of relay 211 further opens the holding circuit for relay 21.0 and the actuating circuit For relay 208 causing their release. The release of relay 208opens the actuating circuit tor relay 20'? causing its release.

It will benoted that the release of relay 210 removes. the ground characterizing the allotter switch terminals as busy. Also the release of relay 208 removes the balancing circuit from the upper leg of the Wheatstone'bridge. Both of these ground circuits are, however, replaced by ground circuits established through the {right inner and outer-armatures and contacts of relay 211.

The' -purpose of" the common connecting unit isto' associate a common sender with Lil one of a plurality of operators positions. At the time the sender is associated with the operators position, a signal is actuated in the operators position. Ihe operator may now actuate the apparatus of the sender over conductors 106 to 110 inclusive to control automatic switches.

As soon as the registers of the sender have been set by the operator the release key 104 is actuated to release relays 1 02 and 211. The release of relay 102 opens the unbalancing circuit established through the lower leg of the Wheatstone bridge and the release of relay 211 opens the balancing circuit established for the upper leg of the Wheatstone bridge. Relay 211 is slow to release so that the opening of the unbalancing circuit will precede the opening of the balancing circuit to prevent the possibility of falsely operating the Wheatstone bridge relay 301.

A number of circuits may be established from various operators positions at one time. Conductors 366 and 367 extend to relays similar to relay 102 located in different operators positions. With grounds connected to conductors 399 and 238 as previously de scribed throughout the selection of a sender, another ground may be connected to conductor 366 to again unbalance the circuit and operate relay 301. This operates the relay in a second connecting unit in the manner of this disclosure and thus a ground is connected to conductor 365 which will again balance the bridge to neutralize the potential in the windings of relay 301. When the relay in the second connecting units similar to relay 210 has been operated. switch magnet 337 is energized to rotate the switch arms to select another idle connecting unit. The same process of unbalancing and balancing the Wheatstone bridge takes place as other operators require the service of connecting units.

Operators may connect ground simultaneously to conductors 238 and 366 causing the bridge circuit to be unbalanced and relay 301 to operate. A connecting unit is thus associated with one of the operators positions and the allotter switch is propelled by switch magnet 337 in the manner previously described, to select another connecting unit. However, in this instance, the ground connected to conductor 399 by the first connecting unit does not balance the bridge and relay 301 remains operated. Upon the selection of a second connecting unit, apparatus in that unit is operated to connect a ground to conductor 365, thus balancing the bridge to release relay 301. It is apparent that when the two connecting units have been assigned to the two operators, ground is connected to conductors 238 and 366 on one side of the bridge and conductors 399 and 365 on the other side of the bridge. In this manner the bridge is balanced to prepare for a third, fourth, etc., actuation of relays the same as relay 102 to associate connecting units and senders with the various operators positions.

What is claimed is:

1. In a telephone system, a plurality of switching devices, an allottcr to determine the order in which said switching devices are put into use, said allotter including a VVheatstone bridge and numerous side circuits, a relay operable when the bridge is electrically unbalanced and capable of restoration when the bridge is electrically balanced, and means for unbalancing and balancing said Viheatstone bridge by electrical connections to its numerous side circuits.

2. In a telephone system, a plurality of switching devices, an allotter to determine the order in which said switching devices are put into use, said allotter including a lVheatstone bridge and numerous side circuits, and a relay operable when the bridge is electrically unbalanced and capable of restoration when the bridge is electrically balanced, means for unbalancing said VVheatstone bridge when electrical connec' tions are made simultaneously to a plurality of side circuits on one side of said bridge, and means for balancing said VVheatstone bridge when the same number of electrical connections are made to a plurality of side circuits on the opposite side of said bridge.

3. In an automatic telephone system, in combination, a plurality of operators positions, a device controlled from said operators positions for making service connections, an allotter to control the action of parts of said device. said allotter including a Wheatstono bric ge and numerous side cir cuits, and a relay operable when the bridge is electrically unbalanced and capable of restoration when the bridge is electrically balanced, and means For unbalancing and balancing said VVhcatstone bridge by electrical connections to its numerous side circuits.

In witness whereof. I hereunto subscribe my name this 19th day of September A. 1)., 1923.

ALBEN E. LUNDELL. 

